134 



KNOWLEDGE. 



[J ONE 1, 1897. 



is now attracting considerable attention, though many 

 improvements will be necessary before this method of 

 locomotion comes into general use. It may be stated 

 briefly that the tendency during recent years is towards 

 the specialization of each detail of the work, special 

 machines being used which are capable of doing their 

 particular item of work nearly automatically. This tends 

 to quickness and accuracy in execution, and is necessary to 

 meet the keen business competition now experienced. 



Pneumatic machines — i.e., machines actuated by com- 

 pressed air — are now used to a limited extent, pneumatic 

 tools for caulking, etc., being very successful. For such 

 operations as riveting, punching, etc., water under pressure 

 is the best agent ; and hydraulic machinery has come 

 largely into use for these and kindred operations. This is 

 one of the most interesting of the developments] of the 



Five Thousand Horse-powi-r Alti-rnalor at Niagara 

 (during construction). 



last lifty years, and our progress here is mainly due to 

 Lord Armstrong. 



i The introduction of the safety bicycle, and the great 

 reduction of frictional waste of energy which has been 

 effected by the use of ball bearings, with other improve- 

 ments, have opened up a new and very important field of 

 engineering construction. 



Another invention of great domestic and business im- 

 portance is that of the sewing machine, the invention of 

 Elias Howe, an American. 



If we seek for some of the causes of our marvellous 

 advance in mechanical engineering and in processfs 

 requiring power, we Hud it, not so much in our superior 

 skill — though that may exist — as in the fict that we get 

 power cheaper than any other people, owing to the lavish 

 gifts of nature in the .shape of coal. Energy (obtained 



mainly from steam) costs in England about one penny per 

 hundred and twelve foot-tons, whereas the like sum in 

 France only purchases seventy-seven foot-tons, in Germany 

 one hundred foot-tons, and in Italy fifty-three foot-tons. 



PROGRESS IN THE IXnUSTRIAL USES OF ELECTRICITY. 



In the applications of electricity to the useful arts one 

 of the most important points to consider is the generation 

 of current. Early methods of obtaining current by the 

 chemical decomposition of certain metals and liquids have 

 very little interest for us now. To Dr. Faraday, who 

 worked so successfully from 1881 to 1840 in this field, is 

 due the great discovery that a current could be induced or 

 set up in a closed circuit by moving a magnet near it, or 

 by using, instead of a magnet, a conductor conveying a 

 current of varying strength. This great discovery, that a 

 current is induced by moving the wire conveying it in a 

 magnetic field of varying strength, is the principle taken 

 advantage of in the modern dynamo machine, which 

 generates — or rather separates for use — most of the electric 

 energy employed in industrial operations. The work of 

 Faraday, Deprez, Siemens, Holmes, Thomson, Ferranti, 

 and others, is so well known as to require no recapitula- 

 tion. Sufiice it to state that the machine has now been 

 brought to a high stage of perfection and efficiency. The 

 general introduction of the electric light (due to the 

 researches of Sir Humphry Davy and otliers) is an appli- 

 cation of great importance, and forms a prominent feature 

 in the industrial progress of the last few years. Applica- 

 tions of current to mechanical operations have already 

 been referred to, and now seem to be opening up a new 

 era of progress. 



The author of the first successful electric motor is not 

 known, but the period of successful development agrees 

 closely with that under review ; for in 1838 one of the first 

 successful attempts was made by .lacobi, who used an 

 electric motor to propel a boat on the River Neva. 



lloliert Davidson, of Abtrdeen, in 1H30, worked a lathe 

 in a similar way ; but we must come down to Faraday's 

 time in ordtr to find a successful motor utilizing current 

 generated by a dynamo. 



The employment of water power at Loch Ness fir the 

 electric production of aluminium from beauxite, and the 

 immense worl;s of the Niagara Falls Power Company at 

 Niagara, are evidences that we are at last becoming .'ilive 

 to the possibilities of natural sources of power, and of 

 electricity as an agent for its transmission. The electric 

 telegraph is, however, probably the most important use of 

 elecoricity inaugurated during the Queen's reign. Whilst 

 we have been slow, in this country, to avail ourselves of 

 the advantages of electrical transmission and distribution 

 of power, in telegraphy we have been always well to the 

 front. 



When Her Majesty ascended the throne, telegraphy — 

 especially submarine telegraphy — was in little more than 

 the experimental stage. It is true that Schilling had, in 

 1812, exploded mines across the River Neva by electric 

 current conveyed under the water by insulated wires ; but 

 little seems to have been done in submarine telegraphy 

 until about 1888, when Colonel Pasley, R.E.. made experi- 

 ments at Chatham which proved that telegraphy was 

 possible through wires laid under water. 



The discovery. by Oersted, in 1810, that a needle is 

 deflected if placed near a wire conveying an electric 

 current ; those of Arago, Ampere, and Sturgeon (1820-2G), 

 showing the magnetization of a needle by the passage of a 

 current round it ; that of Henry in 1830, in which a bent 

 iron bar was made, for the time being, into a magnet by 

 the passage of a current in a conductor enveloping it ; and 

 the further discovery that this magnetizing effect was not 



